This proposal seeks to develop a novel rapid detection system for the identification of antibodies directed against Human T-cell lymphotrophic virus III (HTLV III). It is based on a sandwich fluoro-immunoassay in which an HTLV III antibody containing serum sample is premixed with fluoresceinated HTLV III viral antigen conjugate and subsequently allowed to incubate with an optical grade fiber to which HTLV III viral antigens have been covalently attached. Accumulation of the fluoresceined HTLV III viral antigens on the fiber surface provides a localized concentration of fluorescein which is excited by electromagnetic radiation in the visible wavelength range of 490nm. Fluorescience emission at 525 nm is recaptured by the fiber and propagated the end where it is collected and detected as a light signal output. This system has the potential to become a sensitive, rapid detection assay with simplified sample handling, small sample requirements, and wide field of use in numerous clinical settings including physicians' offices, clinical laboratories, blood banks and field use.